Transcript
Children's sugar consumption halved since tax announcement. Study finds. Headlines like this make me angry. This one's from The Guardian about a 2018 sugar tax in the UK, claiming an effect size large enough to make my skeptic bone tingle. That's a little ways off from a funny bone. Let's check it out. The study in a good journal used data from 8,000 adults and almost as many kids. They tracked food diaries from the National Diet and Nutrition Survey. Self-reporting isn't perfect, but for tracking relative changes, it's not bad. They looked at total added sugar intake and just from soft drinks. The Guardian claim that kids' total sugar intake was cut in half, but the study shows that free sugar from soft drinks only dropped from 22 grams per day to 12 grams per day in kids. Almost half, but the headline didn't say just soft drinks. Total sugar went from 62.4 to 47.8 grams per day, about a 23% drop. But how much of that was due to the tax? The researchers tried to figure it out. They plotted daily sugar consumption since 2008 and saw a steady drop, likely due to increased Here's the tax drop, and this dotted line shows the expected continued drop without the tax. The tax effect is then the difference between those two lines. They concluded, Relative to the counterfactual scenario, there was an absolute reduction in total dietary-free sugar consumption of 4.8 grams per day, or a relative reduction of 9.7% in children. 9.7% is not quite 50%. And I'm harping on this because it's this type of poor journalism that erodes public trust in science. Big claims that don't match up with reality and your intuition make people think that scientists are out of touch. Instead of training them to think, a 10% shift from a public policy change, that's great and could help millions. Science should simplify, not sensationalize. Headlines should clarify, not confuse.
Additional notes
What really gets me is that this article apparently already had its headline amended last week, saying: “The headline and introduction of this article were amended on 10 July 2024. An earlier version said that the amount of sugar consumed by children from soft drinks in the UK halved within a year of the sugar tax being introduced in April 2018. In fact, this halving occurred in the period after the tax was announced (April 2016 to January 2019), compared to the period before the announcement was made (April 2008 to March 2016).” It’s great that they corrected their first mistake, but why not address the REAL PROBLEM?? 📚 Study - DOI: 10.1136/jech-2023-221051 #science #health #nutrition #stem